As the subject says, i am still clueless.  I do have the
7248 booting off my i386 NetBSD firewall via bootp!  But
when it loads, I get the exact same error as when I boot
off of floppies:

init: not found
panic: no init

Now I am thinking that I might have the NFS server
configured the wrong way.  This is what I have:

bootptab:
---------------------------------------------------
ibmrs6k:\
    ht=ethernet:\
    ha=08005AFC541A:\
    ip=192.168.0.100:\
    bf=/sysinst.fs:\
    rp=/export/client/NetBSD-1.6.1/prep:\
    sa=192.168.0.1:

exports
---------------------------------------------------
/export/client/root -maproot=root:wheel    client.test.net
/export/client/swap -maproot=root:wheel    client.test.net
/export/client/usr  -maproot=nobody:nobody client.test.net
/export/client/home -maproot=nobody:nobody client.test.net

I got the exports stuff from following the steps in the
document:  Setting up the NFS server, Diskless NetBSD
HOW-TO

Sam